Field
The present invention relates generally to electrical energy storage devices, and more specifically, to the design of an electrical energy storage device electrolyte and electrode.
Description of the Related Art
Energy storage devices, such as ultracapacitors, can be used to power various electronic devices. Ultracapacitors typically include a first electrode, a second electrode, and a separator impregnated with an electrolyte, the electrolyte facilitating transport of ionic species between the first electrode and the second electrode. For example, the ultracapacitor can store electrical charge in an electrical double layer formed at an interface between an electrolyte and an electrode.
A measure of performance of an energy storage device can include a measure of the ability of the energy storage device to store energy. One such measurement is the energy density of the device. The energy density of an ultracapacitor can depend on the operating voltage of the ultracapacitor, and in general an ultracapacitor with a higher energy density is desirable because it can provide more power in a smaller footprint. In addition, an ultracapacitor with higher energy density may facilitate the use of fewer ultracapacitor cells in powering electronic devices, enabling use of the ultracapacitor to power an increased number of electronic devices, including electronic devices with constrained available space.